winrtinstaller: Set up proper Access Control for install/temp dirs and files

This change addresses:
   https://github.com/KhronosGroup/Vulkan-LoaderAndValidationLayers/issues/70

Also made a change to not require a reboot on uninstall if the install dir
is not empty.  This partially addresses:
   https://github.com/KhronosGroup/Vulkan-LoaderAndValidationLayers/issues/70
(A similar change needs to be made to the SDK installer.)
2 files changed